Computer aided design (CAD) has been widely used to design a component and a product. An analysis using a finite element method can be taken as one of methods for utilizing a three-dimensional CAD model (hereinafter referred to as a CAD model) created by the CAD. If a complicated geometry and/or a minute geometry exists in utilizing the CAD model for analysis, much time is taken up, so that a geometry simplification (hereinafter referred to as simplification, for short) is generally performed in which the complicated geometry and/or the minute geometry is corrected to a simple geometry keeping a calculation accuracy to some extent. When a simplified model in which the CAD model is simplified is used as a numerical analysis model (hereinafter referred to as analysis model, for short), the change in a contact relationship between components made of a conductive material affects a calculation accuracy particularly in an electromagnetic-field analysis, so that an analysis model showing contact relationship similar to the CAD model needs to be created.
Until now, a technique has been known in which interference parts between components are automatically extracted and corrected to correct a geometry after simplification (refer to Japanese Patent Application Laid-Open No. 2008-217709). The technique discussed in Japanese Patent Application Laid-Open No. 2008-217709 is such that interference parts between components are extracted and the geometry of interference parts of the one of interfering components is deleted or the interference parts are divided to the number of the interfering components and an additional process is executed to components corresponding to respective divided parts. Another technique has been known in which clearance or interference between the components that does not exist in the CAD model and appears in creating the analysis model, is eliminated (refer to Japanese Patent Application Laid-Open No. 2006-185276). The technique discussed in Japanese Patent Application Laid-Open No. 2006-185276 is such that, in an analysis model in which the CAD model of each component is divided into a rectangular parallelepiped, if a face which has been brought into close contact in the CAD model is brought into non-close contact, a process is executed to eliminate the part where the face is not in close contact.
In the technique discussed in Japanese Patent Application Laid-Open No. 2008-217709, however, if the components not originally in contact with each other interfere due to the simplification, the components are in contact with each other even if the interfere parts are eliminated. In the technique discussed in Japanese Patent Application Laid-Open No. 2006-185276, although components are not yet brought into close contact in the CAD model, if components are brought into close contact in the analysis model in which the CAD model of each component is divided into a rectangular parallelepiped, the components cannot be corrected to a state where the components are not in close contact, and the components are kept in close contact. There is a problem that much time is taken to create the analysis model because the user manually simplifies and corrects the geometry while visually checking the geometry to prevent change of the contact between the components when creating the analysis model for performing the electromagnetic-field analysis.